The present invention relates generally to charged-particle accelerators, and more particularly it relates to betatrons used for flaw detection in a variety of materials and articles.
It is known in the art to employ betatrons comprising an electromagnet with at least one magnetizing winding and at least one gap defined by the profiled tips of a pair of pole cores, the gap containing therewithin a toroidal vacuum accelerating chamber and at least one bias winding which changes the field distribution within the gas and which is excited together with the magnetizing winding by current pulses produced as an energy accumulator is discharged via switching elements into the mentioned windings.
In these betatrons, the magnetizing winding sets up a time-variable magnetic field in the gap of the electromagnet. Over the section where the field intensity rises, the electrons introduced into the accelerating chamber acquire the required energy. At the instant when the magnetic field intensity is at its maximum, in order to extract the electrons or direct them to the target, current pulses are sent through the bias winding, so that the field distribution in the gap changes and the electrons are displaced from their initial paths. In order to set up these fields, the magnetizing and bias windings are excited by independent current pulse generators, each comprising a control circuit.
The above-described known betatrons are too sophisticated. The independent current pulse generators complicate the circuitry of the betatron, detract from its reliability and also add to the size and weight of the betatron.